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Focal dystonia of the lateral pterygoid muscles treated with botulinum toxin
Author(s) -
MOLLER E.,
DALAGER T.,
FUGLSANGFREDERIKSEN A.,
PRYTZ S.,
WERDELIN L. M.,
BAKKE M.
Publication year - 2002
Publication title -
journal of oral rehabilitation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 93
eISSN - 1365-2842
pISSN - 0305-182X
DOI - 10.1046/j.1365-2842.2002.01026_20.x
Subject(s) - botulinum toxin , medicine , electromyography , pterygoid muscles , digastric muscle , lateral pterygoid muscle , dystonia , blepharospasm , facial muscles , anesthesia , orthodontics , physical medicine and rehabilitation , anatomy , masticatory force , temporomandibular joint , psychiatry
Oromandibular dystonia (OD) is a movement disorder characterized by involuntary activity of the craniofacial muscles. The present study deals with dystonic activity in the lateral pterygoid muscles (LP) of two women causing mandibular overbite, tiredness in the face and chewing and speech difficulties in one (HN, 61 years). In the other (BS, 37 years) OD was characterized by irregular lateral and protrusive jaw movements with and without tooth contact and frequent bilateral headache. By intra‐oral approach and without attempt to distinguish between the two heads the activity of LP was assessed by quantitative electromyography (EMG). Concentric needle electrodes were used for diagnosis and follow‐up, monopolar cannula electrodes for the EMG‐guided injection of botulinum toxin (Botox ® , Allergan Inc., USA). In addition, activity in the temporal, masseter and digastric muscles was recorded with bipolar surface electrodes and mandibular movements were assessed graphically. Compared with reference values of postural activity, OD in both patients was associated with a marked increase in LP. Botox injections resulted in transient reduction of spontaneous and maximal activity, but it took two to three treatments with intervals of 3–4 months to obtain distinct subjective and clinical improvement. However, in HN followed for 18 months after breakthrough of treatment, the effect of the two latest injections lasted 8–9 months or three to four times longer than typical. Using quantitative EMG to locate the abnormal activity and to guide injections, treatment of LP dystonia with botulinum toxin is effective and safe .